Drilling and core removal apparatus and method

ABSTRACT

A drilling and core removal apparatus has a quick-change drill bit release mechanism. A drilling and core removal apparatus has a drill bit and a ground tube within the drill bit, wherein the ground tube having a geometric feature that causes cuttings to be ejected from between the drill bit and the ground tube. A drilling and core removal apparatus has a sensor for indicating that a core sample in a collet tube is approaching a stuck condition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of co-pending U.S. patentapplication Ser. No. 12/143,986, filed Jun. 23, 2008, which published asUS Patent Publication No. US2009/0000822 on Jan. 1, 2009, and whichissues as U.S. Pat. No. 7,934,568 on May 3, 2011, and which claimspriority to U.S. Provisional Patent Application No. 60/937,142, filedJun. 26, 2007, the disclosures of which are incorporated herein byreference.

BACKGROUND

This subject matter disclosed herein relates in general to boring andpenetrating and more particularly to drilling and taking a core sample.

Current core sample removal techniques drill completely through a baserock in order to obtain a core sample. It is often impractical to drillcompletely through the base rock because the depth of the base rock maynot be known, or if it is known, may be far deeper than the desiredsampling depth.

Other current core sample removal techniques drill to a desired depthand rock the drill shaft back and forth until the core sample cracksaway from the base rock. When obtaining a core sample by drilling to thedesired depth and rocking the drill shaft back and forth, severalproblems arise. The cutting annulus must be great enough to providesufficient movement of the drill shaft as it is rocked back and forth.As the cutting annulus size increases, the drill tends to operateslower, work less efficiently, and generate more dust. If the drilldepth is several times greater than the drill diameter, the cuttingannulus must be further increased so as to provide the same rockingangle. Soon it becomes impractical to use this method of core sampleremoval at any depth greater than several drill diameters. Drill shaftflexing will also detract from the available rocking angle.

Other current core sample removal techniques apply relatively largeexternal loads to the drill shaft that must react to ground. Suchsampling techniques can therefore become difficult in sandy or softsurroundings. Additionally, in extraterrestrial environments, many ofthe weight, power and cost restraints make undesirable a drillingapparatus requiring such external loads reacting to ground.

Other current core sample removal techniques subject the core sample tostrong, rotational friction forces while drilling, which can result ininadvertent, premature core breakage. These premature breakages cancause the core sample to become jammed within the collection device.Additionally, the rotational friction forces against the core sample maycause particles to break off of the core sample and accumulate as dust.This dust may clog different parts of the drilling and core removalapparatus rendering either certain parts inoperable or possiblyrendering the entire drilling and core removal apparatus inoperable.

Some current core sample removal techniques do not provide for a drillbit quick-change mechanism. In order to change the drill bit, often theentire drilling and core removal apparatus must be removed from the holeand changed using extra equipment. Some current core sample removaltechniques run the risk of having the drill tube or possibly the entiredrilling mechanism rendered inoperable and immobile if the drill bitgets clogged, broken or otherwise stuck while still in the hole.Additionally, in extraterrestrial environments, the drilling and coreremoval apparatus is often attached to an autonomous research platformwith other pieces of scientific equipment. If the drill bit were tobecome stuck in the hole it was drilling and no drill bit quick-changemechanism were available to release the drill bit while it remainedwithin the hole, then the entire research platform may be renderedimmovable and many of the pieces of scientific equipment may be renderedimmobile and thus inoperable.

Some current core sample removal techniques provide a quick-change meansfor the drill bit, but are unable to obtain the core sample if the drillbit must be released during a drilling operation.

Some current core sample removal techniques do not provide for a stablebushing support to the drill bit during the drilling process.

Some current core sample removal techniques are not reliable enough tobe run autonomously. Reliable and autonomous core sample removaltechniques are particularly necessary in extraterrestrial environments.

Some current core sample removal techniques also require a large numberof moving parts in order to achieve the drilling, core removal, coreejection and drill bit changing actions. The large number of movingparts can increase the cost of the mechanisms, impart a loss of drillingefficiency, increase the cost of necessary repairs and increase thedowntime required for repairs. Additionally, in extraterrestrialenvironments, such a large number of moving parts may be unable tocomply with weight, power, and cost restrictions.

SUMMARY

The invention relates in general to a drilling and core removalapparatus having a quick-change drill bit release mechanism.

A drilling and core removal apparatus has a drill bit and a ground tubewithin the drill bit, wherein the ground tube having a geometric featurethat causes cuttings to be ejected from between the drill bit and theground tube.

A drilling and core removal apparatus has a sensor for indicating that acore sample in a collet tube is approaching a stuck condition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are collectively a perspective view of a drilling andcore removal apparatus.

FIGS. 2A and 2B are collectively a sectional view of the drilling andcore removal apparatus taken along the line A-A in FIGS. 1A and 1B.

FIGS. 3A and 3B are collectively a sectional view of the drilling andcore removal apparatus taken along the line B-B in FIGS. 1A and 1B.

FIGS. 4A and 4B are collectively a partial sectional view of thedrilling and core removal apparatus with a drilling and collecting enddrilled into a work piece or substrate material.

FIG. 4C is a sectional view of a driven end of the drilling and coreremoval apparatus taken along a plane perpendicular to the driven endshown in FIG. 4B, with switch elements or contacts closed.

FIG. 5 is a partial cutaway of a portion of a drill bit and a groundtube.

FIG. 6 is a partial perspective view of a collet tube.

FIGS. 7A and 7B are collectively a partial sectional view of thedrilling and core removal apparatus gripping a core of the work piece orsubstrate material.

FIG. 7C is a sectional view of the driven end of the drilling and coreremoval apparatus taken along a plane perpendicular to the driven endshown in FIG. 7B, with the switch elements or contacts remaining closed.

FIG. 8 is a sectional view of the drilling and collecting end of theapparatus with the core of the work piece or substrate material broken.

FIGS. 9A and 9B are collectively a partial sectional view of thedrilling and core removal apparatus moving a push rod to in turn movethe core of the work piece or substrate material.

FIG. 9C is a sectional view of the driven end of the drilling and coreremoval apparatus taken along a plane perpendicular to the driven endshown in FIG. 9B, with the switch elements or contacts open.

FIGS. 10A and 10B are collectively a partial sectional view of thedrilling and core removal apparatus and core of the work piece orsubstrate material just prior to getting stuck in a collet tube thereof.

FIGS. 11A and 11B are collectively a partial sectional view of thedrilling and core removal apparatus and core of the work piece orsubstrate material just stuck in the collet tube.

FIGS. 12A and 12B are collectively a sectional view of a drill bitrelease mechanism attaching a drill bit to a drill tube.

FIGS. 13A and 13B are collectively a sectional view of a drill bitrelease mechanism releasing the drill bit from the drill tube.

FIG. 14 is a sectional view of a drill bit release mechanism furtherreleasing the drill bit from the drill tube.

FIG. 15 is a sectional view of a drill bit release mechanism releasingthe drill bit from the drill tube.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application or uses. It shouldbe understood that throughout the drawings, corresponding referencenumerals indicate like or corresponding parts and features.

Referring now to the drawings, there is illustrated in FIGS. 1A and 1B adrilling and core removal apparatus 10. The apparatus 10 comprises adriving end 12, shown in FIG. 1A, and a drilling and collecting end 14,shown in FIG. 1B.

Continuing with reference to FIG. 1A, the driving end 12 of theapparatus 10 comprises a transmission 16 and driving gears 18, 20, 22supported in relation to the transmission 16. The driving gears 18, 20,22 are driven by a rotational driving source, such as an external motor(not shown), as will be described in greater detail herein below. Theapparatus 10 is adapted to be moved by an axial driving source, such asan external linear actuator (not shown). Various driving sources andsetups may be suitable, as readily apparent to those skilled in the art.Such driving sources may include DC motors, either brushed or brushless.

The transmission 16, driving gears 18, 20, 22 and associated drivingsources may be enclosed within an enclosure 23 (shown in FIG. 2A). Adrill tube 40 exits the enclosure 23 through a bushing 25 and seal 27,which prevent environmental elements from contaminating the enclosure23. The transmission 16, driving gears 18, 20, 22 and associated drivingsources are subject to linear movement in relation to the enclosure 23by an axial driving source (not shown). The drill tube 40 is subject torotational movement, which is translated to the drilling and collectingend 14 of the apparatus 10 for drilling a work piece or substratematerial S, shown in FIG. 1B.

The transmission 16 comprises a housing 24. The housing 24 generallyincludes a first housing portion 26 (i.e., a lower housing portion whenviewing FIG. 1A) and a second housing portion 28 (i.e., an upper housingportion when viewing FIG. 1A). The housing portions 26, 28 are movablein relation to one another. This movement occurs along a pair of linearguide rods 30. The linear guide rods 30 are supported in relation toaxially spaced guides 32, 34. The guides 32 are diametrically disposedand supported in relation to the second housing portion 28. A helicalspring 36 is carried by each of the linear guide rods 30. Each helicalspring 36 is positioned between a first pair of guides 34 (i.e., theupper guides when viewing FIG. 1A) and stops 37 affixed to ends of thelinear guide rods 30 (i.e., upper ends when viewing FIG. 1A). Oppositeends of the linear guide rods 30 are fixed in relation to the firsthousing portion 26. The housing portions 26, 28 are movable in relationto one another for purposes that will become more apparent in thedescription that follows. The helical springs 36, when in compression,provide a force to urge the housing portions 26, 28 into a directiontowards one another, as will be described below.

Now continuing with reference to FIG. 1B, the drilling and collectingend 14 of the apparatus 10 comprises a drill bit 38 releasably attachedto the drill tube 40 via a drill bit release mechanism 42. The drilltube 40 is driven by the driving gear 18, as will become apparent in thedescription that follows. The drill bit release mechanism 42 will bedescribed in detail in the description herein below.

As shown in FIG. 2A, the first housing portion 26 of the transmissionhousing 24 houses a drill tube driven gear 44, which is supported infixed relation to the drill tube 40 mentioned above, via a drill tubeflange 46 and an inner bearing block 48. Radial bearings 50 arepositioned between the inner bearing block 48 and an outer bearing block52, the latter of which is formed in part by a first end (i.e., a lowerend when viewing FIG. 2A) of the first portion 26 of the transmissionhousing 24. The radial bearings 50 facilitate rotation of the drill tube40 about the longitudinal axis A of the drill tube 40. Rotation of thedrill tube 40, in turn, rotates the drill bit 38 to drill the work pieceor substrate material S, as will be described in detail below.

A ground tube 54 is located concentrically within the drill tube 40. Theground tube 54 is fixed axially and rotationally in relation to a firstsection (i.e., a lower section when viewing FIG. 2A) of the secondportion 28 of the transmission housing 24 by a first locking pin 55,which is fixed axially and rotationally in relation to the ground tube54 and the second portion 28 of the transmission housing 24.

A collet tube 56 is located concentrically within the ground tube 54. Anejection rod or push rod 58, in turn, is located concentrically withinthe collet tube 56. The collet tube 56 and the push rod 58 are fixedagainst rotational movement in relation to the ground tube 54 by asecond locking pin 60 (i.e., a lower locking pin when viewing FIG. 2A).However, the collet tube 56 and the push rod 58 are free to move axiallyin relation to the ground tube 54 because the locking pin 60, thoughaxially fixed in relation to the ground tube 54, extends into anelongated slot 57 (shown in FIG. 4A) in the collet tube 56 and anelongated slot in the push rod 58. As a consequence, the collet tube 56and the push rod 58 are free to move axially in relation to the lockingpin 60, although movement of the collet tube 56 may be more limited thanmovement of the push rod 58, which will become apparent in thedescription that follows.

The collet tube 56 has a driven end (i.e., an upper end when viewingFIG. 2A), which is threaded with an outer thread. A collet tube nut ordriven gear 62, which is threaded with an inner thread, threadablyengages the outer thread on the driven end of the collet tube 56. Thecollet tube driven gear 62 is supported for rotational movement in anaxially fixed position in a second section (i.e., a middle section whenviewing FIG. 2A) of the second portion 28 of the transmission housing 24by thrust bearings 64. The collet tube driving gear 20 may be driven torotate the collet tube driven gear 62. As the collet tube driven gear 62rotates, the inner threads of the collet tube driven gear 62 engage theouter threads on the collet tube driven end to move the collet tube 56axially (i.e., in a vertical direction when viewing FIG. 2A).

The push rod 58 has a driven end (i.e., the upper end when viewing FIG.2A), which is threaded with an inner thread. A lead screw 66, which isthreaded with an outer thread, threadably engages an inner thread of thedriven end of the push rod 58. A driven gear 68 is supported in fixedrelation to a driven end of the lead screw 66. The lead screw drivengear 68 is supported for rotational movement in an axially fixedposition in a third section (i.e., an upper section when viewing FIG.2A) of the second portion 28 of the transmission housing 24 by thrustbearings 69. The lead screw driving gear 22 may be driven to rotate thelead screw driven gear 68. The lead screw driven gear 68 is rotationallyand axially fixed to the lead screw 66. As the lead screw driven gear 68and the lead screw 66 rotate, the push rod 58 moves axially (i.e., in avertical direction when viewing FIG. 2A).

Now with reference to FIG. 3A, there is illustrated a pair ofdiametrically disposed switch assemblies 70, each bridging the first andsecond portion 26, 28 of the transmission housing 24. Each switchassembly 70 includes a first switch element or contact 72 (i.e., a lowerswitch contact when viewing FIG. 3A), which is supported in fixedrelation to the first portion 26 of the transmission housing 24. Asecond switch element or contact 74 (i.e., a upper switch contact whenviewing FIG. 3A) of each switch assembly 70 is supported in fixedrelation to the second portion 28 of the transmission housing 24. Thefirst and second switch contacts 72, 74 electrically communicate withone another when the first and second portions 26, 28 of thetransmission housing 24 are urged into a convergent relationship withone another by the helical springs 36. Conversely, when the first andsecond portions 26, 28 of the transmission housing 24 diverge,electrical communication between the first and second switch contacts72, 74 is broken. The switch contacts 72, 74 are connected to acontroller for controlling the operation of the apparatus 10 (i.e., themotors) based upon the relative positions of the switch contacts 72, 74and the relative positions of the housing portions 26, 28, which isdictated by the occurrence of one or more predetermined conditions, aswill become apparent in the description that follows.

Referring now to FIG. 2B, the drilling and collecting end 14 of theapparatus 10 is shown in cross-section. The drill bit 38 is released ordetached from the drill tube 40 by the drill bit release mechanism 42.The drill bit release mechanism 42 generally comprises a first portion76 supported in fixed relation to an end (i.e., a lower end when viewingFIG. 2B) of the drill tube 40 and a second portion 78 supported in fixedrelation to the shank end of the drill bit 38. The first portion 76 isan active component to the extent that it comprises moving parts, andthe second portion 78 is a passive component to the extent that it hasno moving parts. The first and second portions 76, 78 may be in the formof annular members, as shown in the drawings. The first portion 76 hasdiametrically disposed bores 80 for receiving helical springs 82 and bitlocking pins 84. An enlarged diameter portion 86 of the bit locking pins84 is supported for axial movement within the bores 80. A reduceddiameter portion 88 of the bit locking pins 84 passes through an opening90 in a retaining plate 92 fastened to the first portion 76. Theretaining plate 92 captures the enlarged diameter portion 86 of the bitlocking pins 84 in the bore 80.

The first portion 76 of the release mechanism 42 also supportsdiametrically disposed locking fingers or tabs 94. A first end (i.e., anupper end when viewing FIG. 2B) of the locking fingers or tabs 94 isfixed in relation to the first portion 76 of the release mechanism 42. Asecond end (i.e., a lower end when viewing FIG. 2B) of the lockingfingers or tabs 94 is radially displaceable in relation to the firstportion 76 of the release mechanism 42. The second end of the lockingfingers or tabs 94 has an outwardly directed protrusion 96 that extendsthrough axially extending, elongated slots in the drill tube. Theprotrusion 96 is engageable with an annular groove 98 within the secondportion 78 of the release mechanism 42. The cooperative engagement ofthe protrusion 96 and the annular groove 98 holds the first and secondportions 76, 78 of the release mechanism 42 in an axially fixed relationto one another, which in turn holds the drill bit 38 in an axially fixedrelation to the drill tube 40.

The bit locking pins 84 cooperate with diametrically disposed holes 100(e.g., kidney shaped holes) in the second portion 78 of the releasemechanism 42 to limit or prevent the second portion 78 of the releasemechanism 42 from rotating in relation to the first portion 76. This, inturn, holds the drill bit 38 in a substantially fixed radial relation tothe drill tube 40, thus enabling the drill tube 40 to rotate the drillbit 38.

As will be described in greater detail below, engaging the ground tube54 with the locking fingers or tabs 94 prevents the locking fingers ortabs 94 from deflecting inward. This holds the protrusion 96 incooperative engagement with an annular groove 98.

Use of the drilling and core removal apparatus 10 will now be describedbeginning with reference to FIGS. 4A and 4B. A drill bit 38 is attachedto the drill tube 40. The ground and collet tubes 54, 56 are in drillingpositions, wherein the ground and collet tubes 54, 56 are moved topoints where constricting fingers (described herein below) of the collettube 56 are relaxed so that the inner diameter of the collet tube 56provides unencumbered movement of the core sample S1 into the collettube 56 during the drilling process.

The drill tube driving gear 18 is driven by a motor (not shown). Thedrill tube driving gear 18 meshes with the drill tube driven gear 44.The drill tube driven gear 44 rotates the drill tube 40, which in turnrotates the drill bit 38. The drill bit 38 drills into a work piece orsubstrate material S. The drill bit 38, together with the drill tube 40,the ground tube 54, and the collet tube 56 penetrate the work piece orsubstrate material S, resulting in a core sample S1 to become locatedwithin the collet tube 56. While drilling, a bushing 102 provides a softseal to reduce the risk that foreign matter (i.e., work piece orsubstrate material cuttings) will enter into the clearance space betweenthe inner surface of the drill bit 38 and the outer surface of groundtube 54. The ground tube 54 has flutes 104 that permit discharge of workpiece or substrate material cuttings out from between the drill bit 38and the ground tube 54 (i.e., in the direction of arrow A in FIG. 5).This is referred to as reverse fluting. In addition, the outer surfaceof the drill bit 38 has flutes 106 to discharge work piece or substratematerial cuttings out from between the drill bit 38 and the work pieceor substrate material S (i.e., in the direction of arrow B in FIG. 5).During a normal drilling operation, the switch elements or contacts 72,74 remain closed, as shown in FIG. 4C. An abnormal drilling operation,such as a core sample getting stuck in the collet tube 56, will bedescribed herein below.

During the drilling operation, the ground tube 54 and the collet tube 56are held rotationally fixed with respect to the work piece or substratematerial S so as to provide a non-rotating protective sleeve around thecore sample S1. The non-rotating nature of the ground tube 54 and thecollet tube 56 functions to protect the core sample S1 from inadvertentbreakage and damage, which can cause the core sample S1 to become stuckwithin the drilling and core removal apparatus 10.

After drilling to a desired depth, the collet tube 56 is moved axiallywith respect to the ground tube 54 so that the collet tube 56 grips thecore sample S1, as shown with reference to FIGS. 7A and 7B. Thisgripping function can be accomplished in any suitable manner. Forexample, the collet tube 56 may be provided with constricting fingers108 at the collecting end 14 of the drilling and core removal apparatus10. The constricting fingers 108 may be in the form of slats formed inthe collet tube material. For example, radially spaced, longitudinallyextending slots 110 may define radially spaced constricting fingers 108.Additionally, the constricting fingers 108 may have expanded ends 112and the ground tube 54 may have a conical feature 114 that cooperateswith the expanded ends 112 of the constricting fingers 108 to flex theconstricting fingers 108 radially inwards. It should be appreciated thatthe constricting fingers 108 can vary in design, material and number.Alternative attachment or flexing methods may be used to provideconstricting fingers that flex inwards to create a constriction diameterin the collet tube 56 at the collecting end 14 of the apparatus 10 whena force is applied by the conical features 114 of the ground tube 54.

To move the collet tube 56 (i.e., upward when viewing the drawings), thecollet tube driving gear 20 is driven by the driving source, such as alow speed, high torque reversible motor (not shown). The collet tubedriving gear 20 meshes with the collet tube driven gear 62. The innerthreads of the collet tube driven gear 62 threadably engage the threadson the outer surface of the collet tube 56 to cause the collet tubedriven gear 62 to rotate. As the collet tube driven gear 62 rotates, thecollet tube 56 moves axially (i.e., upward when viewing the drawings).Compare the relative positions of the collet tube 56, the collet tubedriven gear 62, and the threads on the driven end of the collet tube 56shown in FIGS. 4A and 7A.

As the collet tube 56 moves axially, the constricting fingers 108 arephysically pushed radially inwards by the conical features 114, whichtake the form of inclined planes. This inward pushing occurs when thecollet tube 56 is moved with respect to the ground tube 54 (i.e., upwardwhen viewing the drawings). It should be readily apparent to thoseskilled in the art that the required deflection of the constrictingfingers 108 by the conical features 114 may be accomplished through theuse of other constricting finger shapes and materials, other conicalfeature shapes and materials, and other axial movements of the collettube 56 with respect to the ground tube 54. The “constricting fingers”and “conical features” are exemplary features that may take on differentshapes and designs that are not finger-like in nature and that are notconical in nature, respectively.

The relationship between the constricting fingers 108 of the collet tube56 and the conical features 114 of the ground tube 54 cause the collettube 56 to grip the core sample S1 when the collet tube 56 is movedaxially with respect to the ground tube 54 (i.e., upward when viewingthe drawings).

As the collet tube 56 grips the core sample S1, a tension force actingupon the core sample S1 by gripping and axially moving the collet tube56 (i.e., upward when viewing the drawings) breaks the core sample S1from the work piece or substrate material S, as shown along the line 115in FIG. 8.

It should be noted that during a normal drilling operation, the switchelements or contacts 72, 74 remain closed just prior to breaking thecore sample S1, and after the core sample S1 is broken but prior tomoving the push rod 58, as shown in FIG. 7C.

It should be appreciated that this breaking function may be accomplishedwith tension, torsion, or a combination of both tension and torsion, asdescribed in co-pending U.S. patent application Ser. No. 12/143,986,filed Jun. 23, 2008, which published as US Patent Publication No.US2009/0000822 on Jan. 1, 2009, and which issues as U.S. Pat. No.7,934,568 on May 3, 2011, the disclosure of which are incorporatedherein by reference.

After gripping and breaking the core sample S1, the push rod 58 may bemoved (i.e., upward when viewing the drawings) a small distance. To movethe push rod 58, the lead screw driving gear 22 is driven by the drivingsource (not shown). The lead screw driving gear 22 meshes with the leadscrew driven gear 68 to rotate the lead screw driven gear 68, which inturn rotates the lead screw 66. The outer threads of the lead screw 66threadably engage the threads on the inner surface of the push rod 58.As the lead screw 66 rotates, the push rod 58 moves axially (i.e.,upward when viewing the drawings) because the push rod 58 is heldrotationally fixed by the second locking pin 60. Compare the relativepositions of the push rod 58 shown in FIGS. 7A and 9A.

The push rod 58 is moved (i.e., upward when viewing the drawings) untilthe push rod 58 contacts an inner shoulder 116 of the collet tube 56 atthe driving end 12 of the apparatus 10. Continued movement of the pushrod 58 is translated to the second portion 28 of the transmissionhousing 24. If the core sample S1 is broken, the second portion 28 ofthe transmission housing 24 will move in relation to the first portion26, causing the first and second portions 26, 28 to separate. See space118 in FIG. 9A. Also, note in FIG. 9B the space 120, which is indicativethat the core sample S1 is broken and moved a small distance (i.e.,upward when viewing the drawings).

As shown in FIG. 90, the switch elements or contacts 72, 74 open if thecore sample S1 is broken and moves as described above. The open switchcontacts 72, 74 provide a signal to a controller confirming that thecore sample S1 is broken because the switch contacts 72, 74 will notopen unless the second portion 28 of the transmission housing 24 movesin relation to the first portion 26.

It is possible that the gripping force applied by the constrictingfingers 108 against the core sample S1 will be insufficient to preventthe constricting fingers 108 from slipping axially. As a consequence,the collet tube 56 can be actuated to “reset” the grip of theconstricting fingers 108 against the core sample S1 with an increasedforce to again execute the core sample breaking function.

By designing the pitch of the threads 122, 124 on the collet tube drivengear 62 and collet tube 56, as well as the slope of the expanded ends112 of the constricting fingers 108 and the conical features 114 of theground tube 54, the relationship between the gripping force and thetensile force imposed on the core sample S1 can be tailored.

After the core sample S1 is broken free from the substrate S, thedrilling and collecting end 14 of the apparatus 10 can be removed fromthe substrate S. Once removed from the substrate S, the collet tube 56can be moved axially with respect to the ground tube 54 so that theconstricting fingers 108 no longer grip the core sample S1. At thisjuncture, the core sample S1 may simply fall out of the collet tube 56.

It should be understood that the core sample S1 may be pushed out of thecollet tube 56 by the push rod 58. That is to say, the push rod 58 maymove linearly and serve to positively eject the core sample S1 from thecollet tube 56. Moreover, it should be understood that, while drilling,the push rod 58 should be moved (i.e., upward when viewing the drawings)to allow for the length of the core sample S1 to enter the collet tube56. To this end, the range of motion of the push rod 58 should begreater than the desired length of the core sample S1.

In an abnormal drilling operation, the core sample S1 may get stuck inthe collet tube 56. This is undesirable because continued operation ofthe apparatus 10 may lodge the core sample S1 in the collet tube 56 withsuch force that removal of the core sample S1 may be prohibited. As aconsequence, it may be desirable to sense the amount of force with whichthe core sample S1 engages the collet tube 56. This may be accomplishedby appropriately selecting springs 36 for use in combination with thecontact switches 72, 74.

For example, during a normal drilling operation, the springs 36 willexert a desired compression force against the second portion 28 of thetransmission housing 24 to cause the contact switches 72, 74 to remainclosed, as shown in FIGS. 10A and 10B. That is to say, a sample core S1that can move unencumbered within the collet tube 56 should not displacethe collet tube 56. However, a sample core S1 that is encumbered frommovement within the collet tube 56 may exert sufficient force againstthe collet tube 56 to overcome the force of the springs 36, as willbecome apparent with reference to FIGS. 11A and 11B. Continued drillingmay displace the collet tube 56, as depicted by the space 126 shown inFIG. 11B. This displacement will be translated to the second portion 28of the transmission housing 24, which will move in relation to the firstportion 26 of the transmission housing 24. The relative movement of thehousing portions 26, 28 will open the contact switches 72, 74, as shownin FIG. 11A, which will provide a control signal to a controller (notshown) indicating that the core sample S1 in the collet tube 56 isapproaching a stuck condition. By appropriately selecting thecompression force of the springs 36, the amount of force toleratedbetween the core sample S1 and the collet tube 56 can be limited so thatthe drilling operation can be ceased and the drilling and collecting end14 of the apparatus 10 may be removed from the work piece or substratematerial S without breaking the core sample S1 and lodging the coresample S1 in the collet tube 56.

When using the apparatus 10, the drill bit 38 may become worn andotherwise unsuitable for use on a particular work piece or substratematerial S. For these and other reasons, it may be desirable to removethe drill bit 38 from the drill tube 40.

In FIGS. 12A and 12B, the ground tube 54 is shown in a normal drillingposition where its outer wall 128 remains in close contact with thelocking fingers or tabs 94 of the drill tube 40. The protrusion 96engages the annular groove 98. The helical springs 82 urge the bitlocking pins 84 into engagement with the diametrically disposed holes100 to limit or prevent the second portion 78 of the release mechanism42 from rotating in relation to the first portion 76. This, in turn,holds the drill bit 38 in a substantially fixed radial relation to thedrill tube 40, thus enabling the drill tube 40 to rotate the drill bit38.

In FIGS. 13A and 13B, the driving end 12 of the drilling and coreremoval apparatus 10 is shown in a drill bit quick-change position. Thisposition is used to remove the drill bit 38 from the drill tube 40. Itis instructive to note that the ground tube 54, in addition to flexingthe constricting fingers 108 of the collet tube 56, functions to actuatethe drill bit release mechanism 42.

As shown in FIG. 13A, the push rod 58 is moved (i.e., upward whenviewing the drawing) into contact with the second portion 28 of thetransmission housing 24, and further to move the second portion 28 ofthe transmission housing 24 (i.e., upward when viewing the drawing).Referring to FIG. 13B, this movement causes the ground tube 54 andcollet tube 56 to move to a point 130 where the ground tube is recessedin line with the locking fingers or tabs 94 of the drill tube 40 so thatthe drill bit 38 can be released, as shown in FIGS. 14 and 15, such asby moving the drill bit 38 away from the drill tube 40 (i.e., downwardwhen viewing the drawings), or conversely, moving the drill tube 40 awayfrom the drill bit 38 (i.e., upward when viewing the drawings).

It should be apparent to those skilled in the art that different shapesand designs of the ground tube recess 130 may be used to allow thelocking fingers or tabs 94 to deflect inwards and away from the annulargroove 98. It should also be apparent to those skilled in the art thatmany different shapes and designs of locking fingers or tabs 94 may beused to engage many different shapes and designs of one or more recessesor grooves 98 of the drill bit 38 as long as the locking fingers or tabs94 are capable of deflecting inwards when not supported and capable ofeffectively coupling the drill bit 38 and drill tube 40 axially, oraxially and rotationally when supported by the ground tube 54.

It should further be apparent to those skilled in the art that thelocking fingers or tabs 94 and groove 98 may have different designs andshapes and may come in different numbers. Additionally, it should beapparent to those skilled in the art that the locking fingers or tabs 94and groove 98 may either couple the drill tube 40 to the drill bit 38axially or axially and rotationally. If the locking fingers or tabs 94and groove 98 couple the drill tube 40 to the drill bit 38 only axially,then another locking feature, such as the bit locking pins 84, may beused to couple the drill tube 40 to the drill bit 38 rotationally.

To attach the drill bit 38, the drill bit 38 is moved toward the drilltube 40 (i.e., upward when viewing the drawings), or conversely, movingthe drill tube 40 away from the drill bit 38 (i.e., downward whenviewing the drawings). The push rod 58 then is moved (i.e., downwardwhen viewing the drawings) so that the outer wall 128 of the ground tube54 comes into close contact with the locking fingers or tabs 94 of thedrill tube 40 so that the locking fingers or tabs 94 engage the annulargroove 98. Rotating the drill tube 40 will move the bit locking pins 84into registry with the holes 100 in the second portion 78 of the releasemechanism 42, at which point the springs 82 will urge the bit lockingpins 84 into engagement with the holes 100 to rotationally fix the drillbit 38 in relation to the drill tube 40.

It should be appreciated that the drilling and core removal apparatus 10may be used for drilling and core removal in extraterrestrialenvironments. As such, an example of the general scale of the outerdiameter of the drill bit may be about 0.625 inches (1.5875centimeters). It should be appreciated that the drilling and coreremoval apparatus 10 may be scaled up or down in order to accomplishdifferent size core removals. It should also be appreciated that thenature of the drilling and core removal apparatus 10 is not limited touse only in extraterrestrial environments.

In accordance with the provisions of the patent statutes, the principleand mode of operation of the device and method steps have been explainedand illustrated as exemplary embodiments. However, it must be understoodthat the device may be practiced otherwise than as specificallyexplained and illustrated without departing from its spirit or scope.

1. A drilling and core removal apparatus having a quick-change drill bitrelease mechanism.
 2. A drilling and core removal apparatus having adrill bit and a ground tube within the drill bit, wherein the groundtube having a geometric feature that causes cuttings to be ejected frombetween the drill bit and the ground tube.
 3. A drilling and coreremoval apparatus having a sensor for indicating that a core sample in acollet tube is approaching a stuck condition.